Reduce context switching in homekit state updates

[bdraco]

Proposed change

HomeKit state updates were running in the executor
but this does not appear to be needed as value
changes do not do IO and get pushed into a queue
where another thread takes care of updating the
controllers.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Example entry for configuration.yaml:

# Example configuration.yaml

Additional information

• This PR fixes or closes issue: fixes #
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Checklist

• The code change is tested and works locally.
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  Updated and included derived files by running: python3 -m script.hassfest.
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[bdraco]

@MartinHjelmare I had incorrectly assumed that .set_value was doing I/O. I did some more investigation after #34975 and found all the I/O happens in another thread so I think its safe to simplify things a bit. Please let me know if I've missed something here.

https://github.com/ikalchev/HAP-python/blob/dev/pyhap/accessory_driver.py#L432

2020-05-03 18:45:57 DEBUG (MainThread) [pyhap.characteristic] set_value: TargetHeatingCoolingState to 3
2020-05-03 18:45:57 DEBUG (MainThread) [pyhap.characteristic] set_value: CurrentTemperature to 23.3
2020-05-03 18:45:57 DEBUG (Thread-47) [pyhap.accessory_driver] Send event: topic(699270554.10), data(b'{"characteristics": [{"aid": 699270554, "iid": 10, "value": 3}]}'), sender_client_addr(None)
2020-05-03 18:45:57 DEBUG (MainThread) [pyhap.characteristic] set_value: CoolingThresholdTemperature to 22.8
2020-05-03 18:45:57 DEBUG (Thread-47) [pyhap.accessory_driver] Sending event to client: ('192.168.209.53', 58601)
2020-05-03 18:45:57 DEBUG (Thread-47) [pyhap.accessory_driver] Sending event to client: ('192.168.209.57', 56334)
2020-05-03 18:45:57 DEBUG (Thread-47) [pyhap.accessory_driver] Sending event to client: ('192.168.210.42', 63813)
2020-05-03 18:45:57 DEBUG (Thread-47) [pyhap.accessory_driver] Send event: topic(699270554.11), data(b'{"characteristics": [{"aid": 699270554, "iid": 11, "value": 23.3}]}'), sender_client_addr(None)
2020-05-03 18:45:57 DEBUG (Thread-47) [pyhap.accessory_driver] Sending event to client: ('192.168.209.53', 58601)
2020-05-03 18:45:57 DEBUG (Thread-47) [pyhap.accessory_driver] Sending event to client: ('192.168.209.57', 56334)
2020-05-03 18:45:57 DEBUG (Thread-47) [pyhap.accessory_driver] Sending event to client: ('192.168.210.42', 63813)
2020-05-03 18:45:57 DEBUG (Thread-47) [pyhap.accessory_driver] Send event: topic(699270554.14), data(b'{"characteristics": [{"aid": 699270554, "iid": 14, "value": 22.8}]}'), sender_client_addr(None)
2020-05-03 18:45:57 DEBUG (Thread-47) [pyhap.accessory_driver] Sending event to client: ('192.168.209.53', 58601)
2020-05-03 18:45:57 DEBUG (Thread-47) [pyhap.accessory_driver] Sending event to client: ('192.168.209.57', 56334)
2020-05-03 18:45:57 DEBUG (Thread-47) [pyhap.accessory_driver] Sending event to client: ('192.168.210.42', 63813)

[MartinHjelmare]

It's hard for me to comment as I don't have the full picture of this integration and library.